Plural path ink jet writing arrangement

ABSTRACT

A line-writing arrangement wherein the electrostatically deflected jet or jets of ink including a pair of auxiliary electrodes inserted between each jet and the cooperating deflecting electrodes so as to form two different paths to be followed selectively by the jet before it reaches said deflecting electrodes.

United States Patent Inventor Enzo Ascoli Lausanue, Vaud, Switzerland Appl. No. 851,363 Filed Aug. 19, 1969 Patented Apr. 6, 1971 Assignee Palllard S.A.

Sainte-Croix, Vaud, Switzerland Priority Sept. 4, 1968 Switzerland PLURAL PATH INK JET WRITING 511 int. Cl ..G0ld 15/18 [50] Field of Search 346/75; 317/3; 239/3, 15

[56] References Cited UNITED STATES PATENTS 2,573,143 10/1951 Jacob 178/52 3,136,594 6/1964 Ascoli 346/75X Primary Examiner-Joseph W. l-lartary Attorneys-Emory L. Groff and Emory L. Groff, Jr.

ABSTRACT: A line-writing arrangement wherein the electrostatically deflected jet or jets of ink including a pair of auxilia- Fi s ry electrodes inserted between each jet and the cooperating g g deflecting electrodes so as to form two different paths to be U.S. Cl 346/75, followed selectively by the jet before it reaches said deflecting 317/3 electrodes.

Patented. April 6, 1971 3,573,846

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1N VENTOR ENZ ASCOL/ BY I ATTORNEY PLURAL PA'III INK JET WRITING ARRANGEMENT Writing heads operating through jets of ink .are already known as also various methods for the operation of such line writing heads. Writing heads including a body carrying a tube forming a nozzle for the jet of ink and jet-deflecting electrodes located to either-side of the tube axis are described in the US. Pat. applications Ser. Nos. -65l,456;65l,457 and 651,458 .all filed on Jul. 6,1967, now US. Pat Nos. 3,458,760; 3,458,76l and 3,458,762 respectively.

According to a known method for operating writing heads with a view to obtaining writing lines, a single writing head is used which is caused to move in parallelism with theline, the writing of each symbol being performed either during the shifting of the head while the said shifting is compensated by adding a sawtooth voltage to the horizontal component of the symbol to be written-or else during a stoppage of the writing head which moves then intermittently after the manner of the carriage of a writingmachine.

According to another known method for executing such writing heads, a plurality of stationary writing heads are used each of which may write insequence one or more symbols; the method of sequential or simultaneous block writing controlling possibly the whole system of writing heads.

The first method referred to shows generally the drawbacks inherent to the shifting of the writing head along the line, to wit in particular the time lost for the starting and return,'the variations in speed, the necessity of synchronizing the movements of the head with electric signals. Anotherdrawback consists in the presence of mechanical parts such as the motor, the clutch, the magnetic reading. of column spacing. Furthermore the shocks, vibrations and accelerations inherent to the movement of .the head have an objectionable action on the grade of the writing and lead in particular to a dispersion of the jet.

As to the second above-mentioned method, the drawbacks which have been mentioned and which are ascribable to the shifting of ,the head are it is true cut out but, in contradistinction, the arrangement is more intricate since it is necessary to provide a separate feed of ink, high voltages and deflecting voltages for each head. On the other hand, in such an arrangement the reliability factor is divided by the number of transmitting heads.

The present invention has for its object an apparatus for writing lines through the projection and electrostatic deflection of a jet of ink of the type including at least one noulc projecting the jet of ink and a system of electrodes deflecting said jet of ink, the improved arrangement cutting out the abovementioned drawbacks being characterized by the presence of at least two auxiliary electrodes located between the jet and the system of deflecting electrodes, said auxiliary electrodes being adapted to define at least two different paths for the jet of ink before its passage between the deflecting electrodes. According to a preferred embodiment, this improved writing arrangement includes a plurality of nozzles supplying several jets of ink, the auxiliary electrodes being adapted to deflect as required at least one of the jets of ink and to direct it towards the system of deflecting electrodes.

In the latter case, the jets of ink may be of difi'erent colors, the arrangement including two simultaneous outputs of the same color or of different colors.

The accompanying drawing illustrates by way of example several embodiments of the present invention. In said drawings:

FIG. 1 is a horizontal cross section of a first embodiment of the improved writing arrangement.

FIG. 2 is a horizontal cross section of another embodiment.

FIG. 3 illustrates diagrammatically and cross-sectionally a writing head operating with two or three colors.

FIG. 4 illustrates diagrammatically an arrangement including several writing heads according to FIG. 3 and two projecting nozzles.

The arrangement illustrated in FIG. 1 is intended for the writing on a sheet of paper P set over a metal surface M and which is caused to progress upwardly in a plane perpendicular to the plane of FIG. 1. Along the axis aa which is substantially parallel with the line to be written, there are positioned in succession from the right-hand side towards the left-hand side, if the writing is to be executed normally from the left towards the right: ink projecting means 1 and n elements such as 8, 9, 10 the number of which depends on the number of columns into which the writing line is divided.

The projecting means 1 includes chiefly a cylindrical metal chamber 5 serving as a support for an insulating bell-shaped number 4, said chamber 5 being provided with an axial port 6 and with a lateral port 7 for the exhaust of ink deposits. An insulating sleeve 3a forms a support for the metal annulus 2a inside which is set a projecting needle or nozzle 2 fed under a suitable pressure with ink from the pipe 3.

Each of the n elements 8, 9, l0 encloses two auxiliary electrodes such as 8a, 8b,-9a, 9b and 10a, 10b. The electrodes 8a, 9a, 10a are each constituted bya hollow metal body bounded by a cylindrical bore 11 the axis of which registers with aa', a flat vertical surface 12, a portion of a cylindrical surface 13 extending across the bore, a flat horizontal surface 14 and lastly a flat vertical surface .15. The electrode 811 is constituted by a metal body bounded by a cylindrical surface 16 facing the cylindrical surface 13 and extensions on the flat surfaces 14 and 15. The electrodes 8a and 8b are bounded by two parallel planes perpendicular to the plane of FIG. 1 and symmetrical with reference to the axis aa, the arbitrary spacing of which is larger than the diameter of the bore 11. At the left-hand end of the arrangement, there is located an ink trap 17 provided with an exhaust port I8.

In each element, the two electrodes such as 8a and 8b arev separated by a curvilinear channel of which the shape depending on the voltage applied defines the path followed by the particles along a line centered between the walls of said channel. The accurate desired geometrical shape of the channel may be obtained in face through any suitable known means relying on the conventional laws of electronic optics, this forming no part of the present invention.

In front of each lateral outlet of the elements 8, 9, 10 there is located a set of four deflecting electrodes 19 arranged pairwise in opposite relationship in a manner similar to that described in the above-mentioned patent applications.

All the corresponding electrodes are electrically interconnected so that four terminals are obtained, to wit: upper Y, lower Y, right-hand X and left-hand X, which terminals are fed in succession by the electric signals X for the horizontal component and Y for-the vertical component corresponding to the symbol to be written.

As concerns the operation of said arrangement, numerical values are given hereinafter by way of an indication for sake of clarity and simplicity, but it should be understood that said values may be different depending on the geometrical structure and size of the arrangement.

The voltages applied before the writing on the paper is begun are as follows:

Ink: 4,000 volts under a suitable pressure Chamber 5: 1,500 volts Both electrodes of the element 8: 1,400 volts Both electrodes of the element 9: 1,300 volts Both electrodes of the element 10: 1,200 volts and so on up to the nthe element with a linear decrease by volts per element including the trap 17. With such a sequence of voltages, it is apparent that the elements considered as a whole form a linear accelerator for the ink particles passing out of the projecting means and reaching finally the trap 17 so as to be exhausted at 18.

The decrease of the voltages from one element to the next is such that it ensures a substantially constant linear speed for the ink particles in spite of the braking exerted by the air, this being ascribable to the electrostatic forces supplied from one element to the next by the accelerator. At the moment at which the drawing of a symbol of the paper is to begin, the voltages of the two auxiliary electrodes of the element considered are modified while their average voltage remains unchanged.

At the same time, the system of actual writing electrodes 19 assumes the same average voltage as is also the case for the plate M except for a constant. Considering for instance the element out of which it is desired to deflect the stream of ink onto the paper, its average voltage being equal to 1,200 volts and the load carried by the particles being positive and equal to 4,000 volts, it is necessary to increase the voltage of the electrode 10a and to lower that of the electrode 10b. The path followed by the stream of particles has to match the arc of a circle extending medially between the electrodes and consequently the difference in voltage between the latter depends on the geometrical structure of the arrangement, on the speed of the particles and on the load of the latter. Assuming said difference in voltage is equal to 1,000 volts, the voltage of the electrode 100 is then equal to 1,200 500 +l ,700 volts and that of 10b, L200 500 =+700 volts.

From this moment onwards, the stream on the upstream side of the element 10, supplied by the ink projecting means, passes through the system of deflecting electrodes 19 whereas the particles located at such a moment on the downstream side of said element 10 continue their axial progression until they reach the trap 17. The useful stream passing through the writing electrodes may be deflected so as to draw a symbol or even two or three symbols in succession as provided by suitable horizontal biasing operations. Consequently, the duration of shifting of the writing from one column to any other column on the writing line in a direction opposed to the stream and corresponding to the direction of writing corresponds to the duration of the electronic switching of the electrode voltage. In contradistinction, when the direction is the same as that of the stream, the operation is defined by the duration of passage of the stream.

According to a preferred embodiment, the paper is shifted in its own plane during the writing of a line, said shifting being performed at a constant speed in a direction perpendicular to is provided with a port 31b. The electrodes 28a, 29a, 30a and the linear electrode 20 include means securing them onto a support rigid with the writing arrangement.

In front of each outlet such as 28', 29', 30' formed in the linear electrode 20 there is provided as in the first embodiment a system 39 of four writing electrodes adapted to deflect the jet of ink so as to draw the symbols, this being performed each time particles of ink have been deflected through the auxiliary electrode 20 and 28a, 29a and 30a.

In the embodiment considered, the voltage of the deflecting or writing electrodes and of the plate M carrying the paper are held at a constant value; the particles of ink are projected by the nozzle or needle 2 which is subjected to a predetermined voltage. The particles pass then through the first accelerator constituted by the wallsof the chamber 5 and the voltage of the needle and of the first accelerator are caused to vary simultaneously, their difference remaining constant so as to obtain an optimum projection in a manner such that the speed of the particles is constant in the passageway provided by each group of writing electrodes. It is thus possible to overcome the slowing down of the particles produced by the presence of air and which causes as well known in the art a substantially linear decrease of the speed of said particles as they move further away from the projecting needle.

FIG. 3 illustrates diagrammatically a further embodiment including two projecting members and a writing in three colors. The reading head illustrated cross-sectionally is constituted by a main body 40 over which may be fitted two pro- 30 jecting members 41 and 42 of the type described hereinabove.

the line by one line pitch whereas a linearily varying biasing voltage is superposed over the component Y of the symbols to be written whereby the writing may follow the shifting of the paper, the writing being thus stationary with reference to the paper in spite of the translational movement of the latter. This results in that the single mechanical movement is constituted by the slow translational movement of the paper under constant speed conditions, which ensures complete silence during operation as well as a great simplicity in execution.

Since a writing head may write- 100 digits or other symbols per second, a writing line extending over 20 columns for instance may be written in 200 milliseconds. No idle period of any importance can arise during the passage from one line to the next, the arrangement allow five lines to be written per second that is 6,000 symbols per minute. Furthermore, the bulk of the arrangement is substantially less than that of the arrangement used for the execution of the above-mentioned known methods, This arrangement writes on one line in a sequential manner any symbols whatever at any moment whatever and in any location, even if columns on the righthand side or on the left-hand side are left aside.

In the embodiment according to FIG. 2 the arrangement includes a projecting member 1 identical with that described with reference to FIG. I and carrying a projecting needle or nozzle 2 fed with ink as precedingly. One of the auxiliary electrodes is constituted by a linear electrode 20 made of a single part and provided with n notches such as 28, 29, 30. In the different notches the walls 28b, 29b and 30b of which are incurved as illustrated, there are inserted n electrodes 28a, 29a, 30a formed by the latter.

The curves formed by the latter register with the curves defined by the walls 28b, 29b and 30b so as to form curvilinear channels the geometrical design of which is such as to afford the ink particles with a path centered between the walls of said channels.

Each electrode 280 is constituted by two small plates perpendicular to each other, one of which extends in a plane parallel with the axis aa' so as to define a central passageway 31 while the other plate is incurved as already mentioned and Said two projecting members supply two jets of ink of different colors, say blue and red, the ink being fed through pipes 41a and 42a and passing through the projecting needles or nozzles 41b and 42b. Four small plates 43, 44, 45, 46 form the deflecting electrodes for the projected jets of ink. A central electrode 47 cooperates in suitably deflecting the particles. The voltage of said electrode 47 is always positive.

In front of the outlet 5 of the writing head, there is positioned a set of deflecting or writing electrodes 48 of the type described with reference to the first two embodiments. At the other outlet S, the particles are directed towards a target adapted to receive the jet of ink when the latter is not directed towards the writing electrodes.

An adjustment of the positive or negative values of the voltages of the electrodes 43, 44, 45, 46 makes it possible to write with ink of a predetermined color. Assuming red ink feeds the pipe 42a and blue ink feeds the pipe 41a, the particles follow the paths drawn in interrupted lines and it is possible to obtain on the paper beyond the outlet S either a red writing if 45 and 43 are negative while 44 and 46 are positive or else a blue writing when, in contradistinction, 45 and 43 are positive and 44 and 46 are negative or again a red-and-blue or violet writing with 45 and 46 negative and 43 and 44 positive.

As apparent from inspection of diagrammatic FIG. 4, a plurality of writing heads 50, 51, 52, 53 such as those described precedingly may be grouped side by side so as to form a system fed with ink of different colors by two ink-projecting members 54 and 55 arranged respectively at each end of said arrangement.

At the outlet S of each head, the jets of ink which have passed through the writing electrodes draw signs of a predetermined color on the paper covering the metal support M. Similarly, as already described for single writing heads, a target or trap 56 is provided beyond the outlet S in common for the whole system of heads. A suitable adjustment of the voltages of electrodes, which adjustment depends on the logical inputs for the calculator or computer, allows any combination of colors to be obtained on the paper. The embodiment according to this last embodiment allows in particular any symbols to be written on any line at any moment in any column and in any of the three colors provided for each symbol.

According to a modification it is also possible to replace the trap 56 in front of outlet S by a second set of deflectors and a strip of a paper in a manner similar to the deflectors and paper in front of the outlet S the arrangement being symmetrical with reference to the axis M. This last modification allows writing simultaneously on two strips of paper progressing in parallelism upwardly in two corresponding planes perpendicular to the plane of the drawing, the writing being executed with different colors on the two strips.

I claim:

1. An arrangement for writing lines on a sheet of paper on a metal support by means of an ink jet comprising at least one nozzle adapted to project a jet of ink, two pairs of deflecting electrodes associated with said nozzle and pairs of auxiliary electrodes the energization of which is adapted to guide at least one jet of ink selectively along two different paths between said nozzle and said pairs of deflecting electrodes.

2. An apparatus as claimed in claim 1, wherein a plurality of groups of two pairs of deflecting electrodes distributed alongside the axis of the jet passing out of the corresponding nozzle provide parallel passageways for said jet, forming all the same angle with said axis, and the auxiliary electrodes are distributed in pairs registering each with one of said groups to deflect the jet away from its axis into the passageway afforded by said group.

3. An apparatus as claimed in claim 1, wherein a plurality of groups of two pairs of deflecting electrodes distributed alongside the axis of the jet passing out of the corresponding nozzle provide parallel passageways for said jet, forming all the same angle with said axis, and the auxiliary electrodes are distributed in pairs registering each with one of said groups to deflect the jet away from its axis into the passageway afforded by said group, said. pairs of auxiliary electrodes being located along a line coaxial with the jet passing out of the nozzle.

4. An apparatus as claimed in claim 1, wherein a plurality of groups of two pairs of deflecting electrodes distributed alongside the axis of the jet passing out of the corresponding nozzle provide parallel passageways for said jet, forming all the same angle with said axis, and the auxiliary electrodes are dis tributed in pairs registering each with one of said groups to deflect the jet away from its axis into the passageway afforded by said group, said pairs of auxiliary electrodes being located along a line coaxial with the jet passing out of the nozzle, the arrangement including means supplying the nozzle, deflecting electrodes and paper support with voltages such that the speed of the jet particles is the same in all said passageways afforded by the deflecting electrodes.

5. An arrangement as claimed in claim 1, comprising means feeding ink of different colors to different nozzles and means whereby the auxiliary electrodes are adapted to deflect selectively the jet of ink from a predetermined nozzle towards the deflecting electrodes.

6. An arrangement as claimed in claim 1, comprising a target facing the nozzle and adapted to receive the impact of the jet of ink out of said nozzle in the absence of any guiding of said jet towards deflecting electrodes.

7. An arrangement as claimed in claim 1, comprising a target facing the nozzle and adapted to receive the impact of the jet of ink out of said nozzle in the absence of any guiding of said jet towards deflecting electrodes, the groups of deflecting electrodes being distributed in pairs alongside the axis of the jet passing out of the corresponding nozzle to one side at least of said axis and the auxiliary electrodes being distributed pairwise to either side of said axis in registry with the corresponding group of deflecting electrodes symmetrically with reference to the axis of said group to deflect the jet away from its axis between the electrodes of said group. 

1. An arrangement for writing lines on a sheet of paper on a metal support by means of an ink jet comprising at least one nozzle adapted to project a jet of ink, two pairs of deflecting electrodes associated with said nozzle and pairs of auxiliary electrodes the energization of which is adapted to guide at least one jet of ink selectively along two different paths between said nozzle and said pairs of deflecting electrodes.
 2. An apparatus as claimed in claim 1, wherein a plurality of groups of two pairs of deflecting electrodes distributed alongside the axis of the jet passing out of the corresponding nozzle provide parallel passageways for said jet, forming all the same angle with said axis, and the auxiliary electrodes are distributed in pairs registering each with one of said groups to deflect the jet away from its axis into the passageway afforded by said group.
 3. An apparatus as claimed in claim 1, wherein a plurality of groups of two pairs of deflecting electrodes distributed alongside the axis of the jet passing out of the corresponding nozzle provide parallel passageways for said jet, forming all the same angle with said axis, and the auxiliary electrodes Are distributed in pairs registering each with one of said groups to deflect the jet away from its axis into the passageway afforded by said group, said pairs of auxiliary electrodes being located along a line coaxial with the jet passing out of the nozzle.
 4. An apparatus as claimed in claim 1, wherein a plurality of groups of two pairs of deflecting electrodes distributed alongside the axis of the jet passing out of the corresponding nozzle provide parallel passageways for said jet, forming all the same angle with said axis, and the auxiliary electrodes are distributed in pairs registering each with one of said groups to deflect the jet away from its axis into the passageway afforded by said group, said pairs of auxiliary electrodes being located along a line coaxial with the jet passing out of the nozzle, the arrangement including means supplying the nozzle, deflecting electrodes and paper support with voltages such that the speed of the jet particles is the same in all said passageways afforded by the deflecting electrodes.
 5. An arrangement as claimed in claim 1, comprising means feeding ink of different colors to different nozzles and means whereby the auxiliary electrodes are adapted to deflect selectively the jet of ink from a predetermined nozzle towards the deflecting electrodes.
 6. An arrangement as claimed in claim 1, comprising a target facing the nozzle and adapted to receive the impact of the jet of ink out of said nozzle in the absence of any guiding of said jet towards deflecting electrodes.
 7. An arrangement as claimed in claim 1, comprising a target facing the nozzle and adapted to receive the impact of the jet of ink out of said nozzle in the absence of any guiding of said jet towards deflecting electrodes, the groups of deflecting electrodes being distributed in pairs alongside the axis of the jet passing out of the corresponding nozzle to one side at least of said axis and the auxiliary electrodes being distributed pairwise to either side of said axis in registry with the corresponding group of deflecting electrodes symmetrically with reference to the axis of said group to deflect the jet away from its axis between the electrodes of said group. 